BasinStBlue
Well-Known Member
What is the idea behind cutting the center
Divider out of these manifolds ?
Divider out of these manifolds ?
LD 340
- Thread starter BasinStBlue
- Start date
-
Simply put- balance.
Also not the whole divider just a portion.
Also not the whole divider just a portion.
I've always thought it was stupidity.
There have been lots of discussions about the LD. Use the search to find them .
TT5.9mag
Two atmospheres are better than one
There is definitely something to be had.
This screen shot is from the video link below. Lots of good info from Eric.
I would assume that an LD340 would act similarly.
Sure, then use a single plane, instead of mangling a perfectly good intake. The LD340 was designed as a dual plane. "Just because" you can mod it and make more max power doesn't necessarily mean it's always "good" for every build. I've just never agreed with it.
From what I've read(correct me if Im wrong) but chopping out the divider gives more top end, but at the expense of losing some bottom end.
For clearance using a thermoquad carburetor.
Yup, just like a single plane, because that's what you're doing. Basically makin a single plane. Whatever works, I reckon.
Use a spacer
That's a great suggestion. Even a small 1/2" spacer will have the same effect.
Professor Fate
Push the button, Max...
No, the center divider does not need to get touched for a Thermoquad.
It needs the outer edges opened up, here and here.
If you're running a Street Demon or an old Holley 3bbl., then it's a different story- the divider gets trimmed as much as needed for the secondary throttle blade clearance.
Nope. The Street Demon will work fine with the divider.
TT5.9mag
Two atmospheres are better than one
So no one likes actual data? Look at the graph I posted. It gives up nothing down low. Zero, nada. It’s absolutely nothing like a single plane which would throw away 15-20lb/ft compared to an rpm air gap or LD340. It’s a worthy mod that extends the power band up on a dual plane. I’ve also noticed it widens the tuning window a little as well. It doesn’t turn a dual plane in to a single plane, It makes a better dual plane.
You are right, I misspoke thinking Holley 3 barrel and saying thermoquad.
mopowers
Well-Known Member
It's not mangling if it makes more power. It's called hotrodding.
Nope, not right. Both tests were run with an open 1” spacer, so all 4 barrels were open to all 8 cylinders both tests skewing the results for a dual plane with a true divider between 4 barrels of the carburetor. Cutting down the divider just increased the plenum area to 8 cylinders.
I just bought one. It had a holey 3 barrel on it . The carb would not have opened without the notch they put in. The intakes were designed for the 3 bbl. We are thinking of welding it up and run a 4 corner 950. I have the info for the LD340 somewhere I'll post it if I find it.
OMM, if you have the full page of that catalog, can you post the picture of the stelling air cleaners below the manifold and 3 barrel?
I’ve been looking for one for years and cannot find one.
junkyardhero
Well-Known Member
a small notch is generally used as a tuning aid or to clear 2ndary butterflies.
cutting down the divider significantly is more for racing, i'm guessing it was in response to having to run a dual plane manifold in a specific class.
cutting down the divider significantly is more for racing, i'm guessing it was in response to having to run a dual plane manifold in a specific class.
Professor Fate
Push the button, Max...
I'll have to take your word for it, Rusty. I haven't personally run the Street Demon, but just always figured it might need a "touch" on the divider. Still might be wise to put an edge on the divider just to keep the airflow smooth out of the secondary...
Trust me. It works. I have a Street Dominator on my 400 now with a 750 Street Demon. But I had a 351M in it with a Weiand Action plus before I swapped the 400. I had a 625 Street Demon on that one and they have a center divider. Bolted right on and worked fine. Matter of fact, all I had "at first" was the thin mounting gasket and it cleared and worked good, but I put the thicker insulator gasket on it later.
TT5.9mag
Two atmospheres are better than one
-
